A base station included in a radio communication system such as a mobile phone system can be divided into radio equipments (REs) which process a radio signal and a radio equipment control (REC) which controls the REs. A common public radio interface (CPRI) is known as an interface between the REC and the REs (see, for example, Japanese Laid-open Patent Publication No. 2007-312185). With the CPRI an interface between REs and an REC into which a base station is divided is made open. By doing so, many vendors can use each section in a base station.
An REC and REs share slow C&M regions prescribed by the CPRI and exchange monitoring and control information. Accordingly, if one, for example, of REs connected in a daisy-chain fashion occupies slow C&M regions of a monitoring and control signal transmitted or received via the CPRI and transmits monitoring and control information, the other REs cannot insert monitoring and control information in the slow C&M regions. As a result, communication of monitoring and control information is not ensured between the REC and RE.
FIG. 19 is a view for describing occupancy of slow C&M regions of a monitoring and control signal. As illustrated in FIG. 19, REs 111 through 113 are connected to an REC 101 in the daisy-chain fashion. The REC 101 and the REs 111 through 113 transmit or receive monitoring and control information via the CPRI.
The REC 101 includes a monitoring and control processing section 101a. The monitoring and control processing section 101a uses slow C&M regions of a monitoring and control signal transmitted or received via a CPRI link for transmitting monitoring and control information to the REs 111 through 113. In addition, the monitoring and control processing section 101a extracts monitoring and control information transmitted from the REs 111 through 113 from slow C&M regions of a received monitoring and control signal.
Each of the REs 111 through 113 extracts monitoring and control information from slow C&M regions of a monitoring and control signal received via a CPRI link. In addition, each of the REs 111 through 113 inserts monitoring and control information regarding it in slow C&M regions of a monitoring and control signal and transmits the monitoring and control signal via a CPRI link.
It is assumed that the RE 113 inserts a large amount of monitoring and control information in slow C&M regions of a monitoring and control signal. The REC 101 exchanges monitoring and control information with the REs 111 through 113 by sharing slow C&M regions of the monitoring and control signal. Accordingly, the RE 111 or 112 cannot insert monitoring and control information regarding it in slow C&M regions of the monitoring and control signal. As a result, communication of monitoring and control information is not ensured between the REC 101 and the REs 111 through 113.